Any of the documents cited herein are incorporated by reference in their entirety.
A process for the production of Furfural from pentoses using a continuous plug flow reactor is described in U.S. Pat. No. 4,533,743. This patent is also cited in the application WO 2015/020845 A1. This international application is directed to a process for producing furan from furfural from biomass.
A further process for producing furfural from hemocellulose sugars is disclosed in WO 2015/034964 A.
The invention relates to an improved process for the preparation of furfural from a xylose containing feedstock and more particularly to an elevated temperature conversion of a xylose containing feedstock to furfural in acidic conditions. The said process using isophorone or a mixture of two solvents in which condition humins formed are solubilised in the solvents and process is operated in continuous mode with no significant amounts of solid by-products formation.
Furfural is an important renewable and non-petroleum based platform chemical feedstock. It is aldehyde of pyromucic acid with properties similar to those of benzaldehyde. It is widely used as a solvent for refining lubricating oils in petrochemical industry. Furfural is further used as a chemical intermediate in the production of the solvents like furan and tetrahydrofuran. Tetrahydrofuran is further converted to the starting materials used for the preparation of NYLON. Furfural has also been used as fungicidal and weedicidal agents. Furan derivatives such as hydroxymethylfurfural (HMF), furfural and furfuryl alcohol are derived from renewable biomass resources; and serve as building blocks for other potential transportation fuels including dimethylfuran and ethyl levulinate. These derivatives can be used either by themselves or with phenol, acetone or urea to make solid resins. Such resins are used in making fibreglass, aircraft components, automotive brakes, etc.
Conventionally furfural is produced by the dehydration of pentose sugars obtained from cornstalks and corncobs, husks of oat and peanut and other waste biomass stocks [lignocellulosic materials—LCM]. The pentose [C5] fraction of biomass is primarily utilized in bio-refineries to produce furfural, a useful platform chemical produced from the biomass. One of the conventional methods of producing furfural is by acid dehydration of pentosans contained in said biomass. The conventional batch-furfural production process is characterised by high losses of furfural due to the formation of resinous substances called humins, which gives a yield of less than 50%. This process also needs a lot of steam and generates plenty of effluent waste. This method further has a disadvantage of high cost. By another conventional method, furfural is produced by a catalytic process of converting biomass into furfural. This process is a biphasic process, which gives better yield, but the reaction system is homogeneous, corrosive and maximum 10% xylose can be used at the small-scale reactions. Therefore, there is need for more effective and efficient methods of furfural preparation from a variety of biomass feed stocks. With the prior art's methods it has been very difficult to process xylose containing feed streams from LCM with xylose contents of 10% or more, let alone 20% or more.
Further, the humins formed are insoluble in the solvents conventionally used in the preparation of furfural from xylose from LCM biomass. This leads to processes wherein in continuous production process cannot be developed due to accumulation of insoluble humins and heat transfer issues in the system, and therefore, batch processing is performed routinely. The batch processes are expensive and capital intensive compared with continuous processes in bulk chemical industry. Hence, there is need to developing a continuous process for the production of furfural from LCM containing xylose biomass for economic as well as technological benefits.